So after having the obvious point made for me that birds don't need feeding during the summer, I suspended my bird-feeding operation in the backyard until a few weeks ago, as it's now slim pickings for food out there. Unfortunately the slim pickings are impacting the squirrels as well, as they have resumed their assault on my stores of bird seed. The seed is in a metal garbage can after the little rodents ate through the lid on the plastic one I was using, but now they've figured out how to get the lid off. I placed a chunk of cinderblock on the lid, and they've still managed to get in there. I'll have to find a more effective way to keep them out, but in the meantime I'm tempted to rig a camera out there just so I can watch the process of getting the lid off the can.